1. Field of the Invention
The invention relates generally to testing of electronic devices and, more particularly, to a mounting assembly for a test probe which allows multi-directional freedom of motion of the test probe. The invention also relates to a test probe assembly.
2. Background Information
Numerous types of handheld electronic devices are known. Examples of such devices include, for instance, personal data assistants (PDAs), handheld computers, two-way pagers, cellular telephones, and the like. Many handheld electronic devices feature wireless communication capability, although many such handheld electronic devices are stand-alone. In order to assure proper operation, the handheld electronic devices are typically tested as part of their assembly process.
The tests which are conducted on the handheld electronic device often include a test of radio frequency (RF) features and related circuitry of the device. As is known in the art, RF devices enable, among other things, the wireless communication capabilities of the handheld electronic device. Other radio communications enabled by RF devices include, without limitation, navigation communications, satellite communication and navigation and telecommunications, antenna communications, and the like. Testing of handheld electronic device RF features is typically accomplished by way of a switch and probe.
FIGS. 1 and 2 show a representative example of a probe 2, which may be an RF probe, and a switch 4 for testing the wireless communication features of the handheld electronic device (not shown). The probe 2 includes an elongated body 6 with a first, switch engaging end 8, a second end 10 and a mounting plate 12 fixed to the body 6 proximate the second end 10. In the example of FIG. 1, the second end 10 includes a receptacle for connection to, for example, a coaxial cable (not shown). The first end 8 includes a spring-loaded retractable portion 14 having a switch-actuating probe, or wire 16 (FIG. 2). In operation, the retractable portion 14 retracts into the elongated body 6 upon engaging the switch 4 (best shown in FIG. 2), thereby enabling insertion of the wire 16 into the switch 4. The switch 4 may be mounted, on a printed circuit board (PCB) 18, as shown in FIG. 2. The switch 4 includes a receptacle 20 with sloped walls 22, 24 for guiding the probe wire 16 into the switch 4 in order to engage and open a movable contact 26 (FIGS. 3A and 3B).
FIGS. 3A and 3B generally show the movable contact 26 of switch 4. FIG. 3A shows the movable contact 26 in the closed position, while FIG. 3B shows the movable contact 26 in the open position after having been engaged by the probe wire 16. As shown, engaging and opening the switch 4 with the probe wire 16 breaks the circuit, isolating portions of the circuit or device for independent testing.
The probe 2 may be mounted in a stationary position or, alternatively, may be mounted on a robotic arm (not shown) or other suitable movable member. For example, in certain testing circumstances, a series of at least partially assembled handheld electronic devices (not shown) is fed down an assembly line (not shown), with each electronic device stopping at a number of stations including, for example, an RF testing station, in order to be tested one at a time. At the testing station, the probe 2 would be moved to engage the switch 4, which is coupled to the handheld electronic device. In either mounting configuration, the probe 2 is substantially rigid. The rigid manner in which the probe 2 are mounted often results in the probe 2 becoming damaged during a testing sequence.
Specifically, the probe 2 is typically rigidly mounted to the stationary structure or the robotized structure (not shown) by fasteners, such as screws (not shown), which are inserted through holes 28,30 in the mounting plate 12. Such rigid mounting of the probe 2 neglects to provide sufficient freedom of movement of the probe 2 and, therefore, renders the probe incapable of accommodating misalignment between the probe 2 and the device under test (DUT) and, more particularly, misalignment between the switch 4 on the DUT, and the probe 2. Due to the small size of the components involved, i.e., the switch 4, the probe 2 and, in particular, the wire 16, misalignment can easily occur, and in fact, frequently does occur. The small and thus fragile nature of the probe wire 16 renders it particularly susceptible to damage during testing sequences. Specifically, when misaligned, as shown in FIG. 2, the probe wire 16 bends (not shown) upon hitting an adjacent portion of the switch 4 (e.g., sloped side walls 22,24). Although the rectractable portion 14 of the probe 2 includes a conical shaped recess 32 having sloped sides 34,36 which are adapted to assist in centering the probe 2, perfect alignment and insertion of the probe wire 16 through the center of the switch receptacle 20 is seldom achieved. The rigid nature of the probe 2, therefore, tends to result in the misaligned wire 16 being bent. Bending the wire 16 can damage (e.g., yield) and even break it. Bending also creates problems when the wire 16 is retracted following testing and when an attempt is made to re-aim the wire 16 during a subsequent testing sequence.
There is a need, therefore, for a probe mounting assembly and probe capable of accommodating misalignment between the probe and the DUT, and for an associated method of employing the probe.